What is Hyperbaric Oxygen Therapy?

Hyperbaric oxygen therapy (HBOT) is the use of high pressure oxygen as a drug to treat basic pathophysiologic processes and their diseases (4). HBOT has acute and chronic drug effects (5). Acutely, HBOT has been proven to be the most powerful inhibitor of reperfusion injury (6,7,8,9), which is the injury that occurs to tissue deprived of blood supply when blood flow is resumed. This is thought to be one of the primary mechanisms of hyperbaric oxygen therapy effects in acute global ischemia, anoxia, and coma (4). Chronically, HBOT acts as a signal inducer of DNA to effect trophic (growth) tissue changes (10,11,12,13,14,15). Among the demonstrated effects in chronic wounding is the development of new blood vessels (16), however; in the brain preliminary animal evidence seems to suggest more of an adaptive effect on metabolism and blood flow (17). For discussion of this, see Chapter 18 of the K.K. Jain textbook. Please note errata in Chapter 18: In each case study HBOT was delivered at a maximum frequency of twice/day, not the four times/day erroneously mentioned.

Drs. Harch, Neubauer, and Van Meter are authors of three chapters in the K.K. Jain Textbook of Hyperbaric Medicine (4). None of them receive royalties from the sales of the book. This textbook is one of the most comprehensive and authoritative textbooks on HBOT, especially neurological applications, and contains over 1700 references.

4. Harch PG and Neubauer RA. Hyperbaric oxygen therapy in global cerebral ischemia/anoxia and coma, Chapter 18. Textbook of Hyperbaric Medicine, 3rd Edition. Editor: K.K. Jain. Hogrefe and Huber Publishers, Seattle, 1999.

5. Hyperbaric Oxygen Therapy: 1999 Committee Report. Editor, N.B. Hampson. Undersea and Hyperbaric Medical Society, Kensington, MD.

6. Zamboni WA, et al. Morphological analysis of the microcirculation during reperfusion of ischemic skeletal muscle and the effect of hyperbaric oxygen. Plast Reconstr Surg 1993;91:1110-1123.

7. Thom SR. Functional inhibition of leukocyte B2 integrins by hyperbaric oxygen in carbon monoxide-mediated brain injury in rats. Toxicol Appl Pharmacol 1993;123:248-256.

8. Mink RB, Dutka AJ. Hyperbaric oxygen after global cerebral ischemia in rabbits reduces brain vascular permeability and blood flow. December, 1995. Stroke;26(12):2307-2312.

9. Yamada T, et al. The protective effect of hyperbaric oxygenation on the small intestine in ischemia-reperfusion injury. Journal of Ped Surg, June, 1995;30(6):786-90.

10. Siddiqui A, et al. Ischemic tissue oxygen capacitance after hyperbaric oxygen therapy: a new physiologic concept. Plast Reconstr Surg, 1995;99:148-155.

11. Wu L, Mustoe TA. Effect of ischemia on growth factor enhancement of incisional wound healing. Surgery, 1995;117:570.

12. Buras JA, et al. Hyperbaric oxygen downregulates ICAM-1 expression induced by hypoxia and hypoglycemia: the role of NOS. Am J Physiol Cell Physiol. 2000;278:292-302.

13. Zhao LL, et al. Effect of hyperbaric oxygen and growth factors on rabbit ear ischemic ulcers. Arch Surg, 1994;129:1043.

14. Reenstra WR, et al. Hyperbaric oxygen increases human dermal fibroblast proliferation, growth factor receptor number and in vitro wound closure. Undersea & Hyperb Med, 1998a;25:53.

15. Reenstra WR, et al. Hyperbaric oxygen increases human dermal fibroblast expression of EGF-receptors (EGFR). Undersea & Hyperb Med, 1998b;25:54.

16. Marx RE, et al. Relationship of oxygen dose to angiogenesis induction in irradiated tissue. Am J Surg, 1990;160:519-524.

17. Harch PG, et al. Low pressure hyperbaric oxygen therapy induces cerebrovascular changes and improves complex learning/memory in a rat open head bonk chronic brain contusion model. Undersea and Hyperbaric Med, 1996;23(Suppl):48.